Means for coupling a cavity resonator to a conductor circuit and/or a further cavity resonator

ABSTRACT

Means for coupling a cavity resonator to a conductor circuit and/or a further cavity resonator wherein a coupling window or opening is present at the wall between the cavity resonator and the conductor circuit and/or the further cavity resonator. According to the invention the coupling window or opening possesses a cross-section which at least approaches a U- or Vshape having a tongue, the axis of symmetry of which is at least approximately parallel to the vector of the electrical field of the resonator at the region of the coupling window or opening. The length of the tongue is chosen such that the tongue together with the coupling window forms a lambda /4 resonant circuit working with the TEM-mode. The method of tuning the coupling according to the invention contemplates bending or rotating the tongue so as to change the coupling factor.

1. ite States I-Iadbavny et a1.

aten 1 1 1451 Jan. 15,1974

[75] Inventors: Jozef Hadlbavny; Peter Fuglister,

both of Zurich, Switzerland [73] Assignee: Siemens-Albis AG, Zurich,

Switzerland 22 Filed: Sept. 7, 1972 211 App]. No.: 287,031

[30] Foreign Application Priority Data Oct. 14, 1971 Switzerland 015080/71 [52] US. Cl. 333/24 R, 333/24'C, 333/82 B, 333/83 R, 333/98 R [51] Int. Cl .1101]: 5/02, HOlp 5/08, I-I0lp 7/06 [58] Field of Search 333/98 R, 24 R, 83 R, 333/73 W, 21 R, 84 M, 17 L; 343/767 [56] References Cited UNITED STATES PATENTS 2,423,130 7/1947 Tyrrell 333/73 W 2,877,429 3/1959 Sommers et a1. 333/21 R 2,560,353 7/1951 Kerwien 333/21 R 3,448,414 6/1969 Brunton 333/17 L 3,160,826 12/1964 Marcatili 333/83 R FOREIGN PATENTS OR APPLICATIONS 655,045 7/1951 Great Britain 343/767 1,015,163 8/1952 France 343/767 OTHER PUBLICATIONS Allen et al., On the Theory of Strongly Coupled Cavity Chains MTT-8, 5-1960 pp. 362-372.

Ragen, G. L. Microwave Transmission Circuits, McGraw Hill, 1948, pp. 688-690.

Southworth, G. C. Principles & Applications of Waveguide Transmission, D. Van Nostrand, 1950, pp. 254- 255.

Primary Examiner.1a.rnes W. Lawrence Assistant ExaminerWm. I-I. Punter Att0rney-Werner W. Kleeman 5 7] ABSTRACT Means for coupling a cavity resonator to a conductor circuit and/or a further cavity resonator wherein a coupling window or opening is present at the wall between the cavity resonator and the conductor circuit and/or the further cavity resonator. According to the invention the coupling window or opening possesses a cross-section which at least approaches a U- or V- shape having a tongue, the axis of symmetry of which is at least approximately parallel to the vector of the electrical field of the resonator at the region of the coupling window or opening. The length of the tongue is chosen such that the tongue together with the coupling window forms a 7\/4 resonant circuit working with the. TEM-mode. The method of tuning the coupling according to the invention contemplates bending or rotating the tongue so as to change the coupling factor.

3 Claims, 16 Drawing Figures Pmmmm 151924 3.786371 saw a or z Km F/G. 9/1

MEANS FOR COUPLING A CAVITY RESONATOR TO A CONDUCTOR CIRCUIT AND/OR A FURTHER CAVITY RESONATOR BACKGROUND OF THE INVENTION The present invention relates to a new and improved means for coupling a cavity resonator to an energy transmission device, such as a conductor circuit or a further cavity resonator and to a method of tuning such coupling.

With known couplings between cavity resonators and waveguides and/or further cavity resonators, there are provided either round or rectangular coupling windows or openings. These coupling windows or openings, also known as iris, transmit fields of random polarization direction. For this reason it is possible that apart from the desired type of wave or mode there are also transmitted undesired modes in the cavity resonator.

Furthermore, there are known to the art couplings between the above-mentioned resonators and coaxial lines, wherein the internal conductor, designed as a coupling loop, extends into the internal cavity or compartment of the resonator.

Also this constructional embodiment has the drawback that owing to the coupling there are energized different undesired modes.

SUMMARY OF THE INVENTION Hence it is a primary object of the present invention to provide new and improved means for coupling a cavity resonator to a conductor circuit or a further cavity resonator in a manner which is not associated with the aforementioned drawbacks and limitations of the prior art proposals.

Another and more specific object of the present invention aims at the provision of a coupling between a cavity resonator and a conductor circuit or a further cavity resonator which does not transmit any undesired modes.

Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the inventive coupling is manifested by the features that the coupling window or opening possesses a cross-section which at least approaches a substantially U- or V-shaped configuration and has a tongue, the axis of symmetry of which is directed at least approximately parallel to the vector of the electrical field of the resonator at the region of the coupling window or opening. The length of the tongue is selected such that the tongue together with the coupling window forms a M4 resonant circuit operating with the TEM-mode.

With the inventive coupling there are only transmitted waves, the electrical fields of which are disposed parallel to the axis of symmetry of the tongue. There is thus present the advantage that disturbing higher modes are not energized. By virtue of the fact that the tongue together with the window or opening forms a )t/4-resonant circuit operating or working with the TEM-mode there is effective within the resonance region of this circuit a higher coupling factor, whereas outside of resonance there is only effective a very low coupling factor. Since the circuit quality of the aforementioned A/4-resonant circuit is low, the region of high coupling factor is relatively wide.

By means of the inventive coupling, there is possible a direct transmission of TEM-modes to a cavity resonator without coupling loops or probes extending into the cavity of the resonator. Hence, in contrast to the loop coupling there is present the advantage that the field pattern of the resonator, which possesses a high quality, is not unfavorably deformed by coupling elements which extend into the cavity or hollow compartment.

The transmission to a coaxialor strip-line can be realized in a very simple manner in that between the tongue and the internal conductor of the line there is produced a hybrid coupling or a galvanic connection.

The technique for tuning the coupling contemplates displacing the tongue, namely bending or rotating same, so as to change the coupling factor.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

FIG. I illustrates a cavity resonator coupled to a strip-line or conductor as viewed substantially along the line [-1 of FIG. IA;

FIG. IA illustrates the cavity resonator arrangement depicted in FIG. 1;

FIG. 2 illustrates a cavity resonator coupled to a coaxial line as viewed substantially along the line IIII of FIG. 2A;

FIG. 2A illustrates the cavity resonator arrangement depicted in FIG. 2;

FIG. 3 illustrates a cavity resonator coupled to a waveguide as viewed substantially along the line III-III of FIG. 3;

FIG. 3A illustrates the cavity resonator arrangement depicted in FIG. 3;

FIG. 4 illustrates a cavity resonator coupled with a diode as viewed substantially along the line IV-IV of FIG. 4A;

FIG. 4A illustrates the cavity resonator arrangement of FIG. 4;

FIGS. 5 to 8 inclusive respectively illustrate on an enlarged scale different coupling windows or openings;

FIG. 9 illustrates a cavity resonator coupled with a diode and constituting a hybrid coupler and as viewed substantially along the line IX-IX of FIG. 9A;

FIG. 9A illustrates the cavity resonator arrangement of FIG. 9;

FIG. I0 illustrates a modified arrangement of cavity resonator coupled with a semiconductor element or microwave detector element as viewed substantially along the line X)( of FIG. 10A; and

FIG. 10A illustrates the cavity resonator arrangement of FIG. I0.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now the drawings, the cavity resonator 3 illustrated in FIG. 1 is provided for the excitation of a TEOlnmode, wherein the electrical field ER extends concentrically with respect to the wall of the cavity. The jacket of the circular cavity resonator 3 is provided at its outside with a flat surface 3a which, for instance, can be produced by milling or otherwise suitably machining the jacket until reaching a lesser thickness of the wall. The wall is pierced by a substantially U- shaped coupling window or opening 1. The U-shape of this coupling opening 1 is formed by a rectangular opening having an inwardly protruding tongue 2, as such has been illustrated on an enlarged scale in FIG. 5. The coupling window or opening 1 is arranged such that the symmetry axis A of the tongue 2 is disposed parallel to the vector of the electrical field ER which is present at the resonator at the region of the coupling window 1. The length of the tongue 2 is chosen such that together with the coupling window it forms a M4- resonant circuit operating with the TEM-mode. At the surface 6 there is secured a non-symmetrical strip line 4. This strip line 4 is arranged relative to the tongue 2 such that the strip-shaped line or conductor of the strip-line 4 extends at a small spacing parallel to the axis of symmetry A of the tongue 2. The strip-line 4 together with the tongue 2 forms a hybrid coupler. The surface conductor 8 defined by the strip-line 4 is galvanically connected with the resonator mass or body.

Now according to a different constructional embodiment, instead of the hybrid coupler, the conductor 5 is galvanically connected with the tongue 2.

The resonator 3 depicted in the embodiment of FIG. 2 corresponds to that of FIG. 1. However, it possesses a circular coupling window or opening 1 with the inwardly protruding or projecting tongue 2, as such has been shown on an enlarged scale in FIG. 8. A coaxial line 10 with an internal conductor 12 and an outer sleeve or jacket 11 is coupled to the resonator 3. The internal conductor 12 is welded to the tongue 2 and the outer sleeve or jacket 11 is welded to the surface 6.

According to a different physical manifestation of the invention, the internal conductor 12 of the coaxial line 10 is arranged at a slight spacing from the tongue 2 parallel to the axis of symmetry A of such tongue. The internal conductor 12 together with the tongue 2 forms a hybrid coupler.

The resonator 3 illustrated in the exemplary embodiment of FIG. 3 corresponds to that of FIG. 1. However, in this case it possesses a V-shaped coupling window or opening 1, as such has been illustrated in FIG. 7 on an enlarged scale. The resonator 3 is coupled with a rectangular waveguide 21. The waveguide 21 is mounted at the end at the jacket or wall of the resonator 3 and suitably connected therewith. The cross-section of the waveguide 21 is directed such that the vector of the electrical field EW of the HlO-mode at the waveguide 21 is disposed parallel to the vector of the resonator field ER at the coupling window or opening 1.

In FIG. 4 there is illustrated the coupling of a diode 31 at the cavity resonator 3. The coupling window or opening 1 possesses a circular-shaped cross-section with an inwardly protruding tongue 2. The axis of symmetry A of the tongue 2 is again directed parallel to the vector of the electrical field ER in the resonator 3 at the coupling window or opening 1. At the edge of the window opposite the tongue 2 there is mounted a crystal diode 31, as best seen by referring to FIG. 4. The one diode connection or terminal, consisting of a wire 32, is connected in a high-frequency manner with the tongue 2. The second connection or terminal is formed by a metal coating or layer 33 vapor deposited at the diode body. This metal coating or layer 33 bears against the edge of the window or opening 1, so that there is produced the contact with the resonator mass.

Instead of the galvanic coupling arrangement depicted in FIGS. 4 and 4A there is shown in FIGS. 9 and 9A a different coupling arrangement wherein coupling of the semiconductor, here in the form of a diode 31, occurs by means of a so-called hybrid coupler, in other words a coupler wherein the coupling action occurs partially inductively and partially capacitively. In this instance a connection or terminal 36 of the diode 31 is guided at a small spacing from the tongue 2 parallel to the axis of symmetry thereof. In order to maintain such spacing there is bonded to the outside surface of the resonator 3 an insulating plate 35. The extended connection or terminal 36 of the diode 31 is secured to this insulating plate 35. In this case the coupling does not occur exclusively via the connection or terminal 36, rather partially by means of the diode 31 itself because such is located at the field 37 concentrated about the tip of the tongue 2.

FIGS. 10 and 10A illustrate a cavity resonator arrangement wherein a microwave detector element 31 such as a conventional diode, bolometer, thermistor, is arranged in the region of the concentrated field at the neighborhood of the tip of the tongue 2 wherein such microwave detector element is influenced in known manner by such field. This arrangement can be employed whenever a small coupling action is sufficient.

With the type of coupling window or opening 1 illustrated in FIG. 8 the dimensions were determined experimentally. The tongue 2 possesses a semi-circular shaped end portion 41 and side or end surfaces 42 and 43 parallel to the axis of symmetry A. Both side surfaces 42, 43 transform at the root of the tongue 2 in the form of cylindrical jacket or wall surfaces 44, 45, respectively, into the circular-shaped window or opening 1. The spacing d2 of the end portion 41 of the tongue 2 with regard to the oppositely situated edge of the window 1 and the diameter d3 of the respective cylindrical jackets 44 and 45 are equal to the width d1 of the tongue 2. The sum from the diameter D of the window or opening 1 and one-half of the width done-half of the tongue 2 is equal to or smaller than one-quarter of the wavelength (A4).

The tongue 2 must be accordingly selected to be shorter than the theoretical length M4. The reason for such shortening appears to be that as the effective capacitance there is also present the stray capacitance of the tongue 2.

It is here also to be mentioned that in FIG. 6 there is disclosed a coupling or window opening 1 having a substantially oval cross-section and equipped with the inwardly protruding tongue 2.

The invention also provides the possibility of tuning the coupling by changing the positional orientation of the tongue so as to alter the coupling factor, for instance by bending or rotating such tongue.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims. Accordingly, What is claimed is:

1. Means for coupling a cavity resonator to an at least two terminal semiconductor element, wherein a coupling window is present at the wall between the cavity resonator and the semiconductor element, said coupling window possessing a predetermined cross-section and having a tongue, the axis of symmetry of the tongue extending at least approximately parallel to the vector of the electrical field of the resonator at the region of the coupling window, the length of said tongue being selected such that the tongue together with the coupling window forms a M4 resonant circuit operating with the TEM-mode, and wherein at least one terminal of said semiconductor element is located at a small spacing from the tongue at least approximately parallel to the axis of symmetry of the tongue and forms therewith a hybrid coupler.

2. Means for coupling a cavity resonator to an at least two terminal semiconductor element, wherein a cou pling window is present at the wall between the cavity resonator and the semiconductor element, said coupling window possessing a predetermined cross-section and having a tongue, the axis of symmetry of the tongue extending at least approximately parallel to the vector of the electrical field of the resonator at the region of the coupling window, the length of said tongue being selected such that the tongue together with the coupling window forms a M4 resonant circuit operating with the TEM-mode, and wherein at least one terminal of said semiconductor element is galvanically connected with the tongue.

3. Meansfor coupling a cavity resonator to a microwave detector element, wherein a coupling window is present at the wall between the cavity resonator and the microwave detector element, said coupling window possessing a predetermined cross-section and having a tongue, the axis of symmetry of the tongue extending at least approximately parallel to the vector of the electrical field of the resonator at the region of the coupling window, the length of said tongue being selected such that the tongue together with the coupling window forms a )\/4 resonant circuit operating with the TEM- mode, and wherein said microwave detector element is arranged at and energized by the near field about the tip of the tongue.

Patent No. 3,786,371 Dated January 15, 1974 Invent-(5) Jozef Hadbavny and Peter Fuglister It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as. shown below:

Column 2, line 62, read "TEOlnmode" as --TE -mode-- Column 2, line 64 after "outside" insert --3a--.

Column 2, line 64, after "surface" read "3a" as --6-- Column 4, line 38, read "done-half" as -dl- Column 4, line 40, read "A4" as \/4- The attached sheet containing Figures 4, 4A, 5, 6, 7

and 8 is part of the original Letters Patent.

Signed and sealed this 15th day of April 1975.

SEAL.)

Attestr C. I-IARSHALL BANK RU'IEI C. 'PLASON Commissioner of Patents (attesting Officer and Trademarks FORM $69) uscoMM-oc scan-poo i ".5. GOVIIIIIIIT PRINTING OIFICI 5 III O-IC-JI 

1. Means for coupling a cavity resonator to an at least two terminal semiconductor element, wherein a coupling window is present at the wall between the cavity resonator and the semiconductor element, said coupling window possessing a predetermined cross-section and having a tongue, the axis of symmetry of the tongue extending at least approximately parallel to the vector of the electrical field of the resonator at the region of the coupling window, the length of said tongue being selected such that the tongue together with the coupling window forms a lambda /4 resonant circuit operating with the TEM-mode, and wherein at least one terminal of said semiconductor element is located at a small spacing from the tongue at least approximately parallel to the axis of symmetry of the tongue and forms therewith a hybrid coupler.
 2. Means for coupling a cavity resonator to an at least two terminal semiconductor element, wherein a coupling window is present at the wall between the cavity resonator and the semiconductor element, said coupling window possessing a predetermined cross-section and having a tongue, the axis of Symmetry of the tongue extending at least approximately parallel to the vector of the electrical field of the resonator at the region of the coupling window, the length of said tongue being selected such that the tongue together with the coupling window forms a lambda /4 resonant circuit operating with the TEM-mode, and wherein at least one terminal of said semiconductor element is galvanically connected with the tongue.
 3. Means for coupling a cavity resonator to a microwave detector element, wherein a coupling window is present at the wall between the cavity resonator and the microwave detector element, said coupling window possessing a predetermined cross-section and having a tongue, the axis of symmetry of the tongue extending at least approximately parallel to the vector of the electrical field of the resonator at the region of the coupling window, the length of said tongue being selected such that the tongue together with the coupling window forms a lambda /4 resonant circuit operating with the TEM-mode, and wherein said microwave detector element is arranged at and energized by the near field about the tip of the tongue. 